Abstract
The physical properties of the crystalline phases are strongly dependent on the symmetric arrangement of the atomic species in the solid, the distribution of the intervening chemical bonds, and the overall chemical composition. In the Fe(Se,Te) system, the parent compound Fe 1+y Te crystallizes in the tetragonal system at room temperature, but on cooling different structural transitions are observed, depending on the amount of the Fe-interstitial content. In particular, the amount of the interstitial Fe strongly controls the amplitude of the different symmetry-breaking modes intervening in the structural transitions. On the other hand, these modes are progressively suppressed by the substitution of Te with Se. The structural transition characterizing the 1111-type systems exhibit significant differences: the displacive mode that should drive the symmetry-breaking is not involved in any atomic displacement, but an abrupt increase of lattice microstrain occurs along the tetragonal hh0 direction in LnFeAsO compounds just above the structural transformation; this strain is then suppressed by symmetry breaking. It is generally accepted that above a critical amount of electron doping (induced by F substitution), the tetragonal to orthorhombic transition is suppressed. Recently, we found strong experimental evidences that the orthorhombic distortion is actually strongly reduced with doping, but not suppressed, reconciling the apparently contradictory findings reported in literature for the tetragonal to orthorhombic transition in electron and hole-doped compounds.
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Bao, W., Qiu, Y., Huang, Q., Green, M.A., Zajdel, P., Fitzsimmons, M.R., Zhernenkov, M., Chang, S., Fang, M., Qian, B., Vehstedt, K.E., Yang, J., Pham, H.M., Spinu, L., Mao, Z.Q.: Tunable (δ π,δ π)-Type antiferromagnetic order in α-Fe(Te,Se) superconductors. Phys.Rev. Lett. 102, 247001 (2009)
Martinelli, A., Palenzona, A., Tropeano, M., Ferdeghini, C., Putti, M., Cimberle, M. R., Nguyen, T.D., Affronte, M., Ritter, C.: From antiferromagnetism to superconductivity in Fe 1+y Te 1−x Se x (0 ≤×≤0.20): neutron powder diffraction analysis. Phys. Rev. B 81, 094115 (2010)
Koz, C., Rößler, S., Tsirlin, A.A., Wirth, S., Schwarz, U.: Low-temperature phase diagram of Fe 1+y Te studied using x-ray diffraction. Phys. Rev. B 88, 094509 (2013)
Rodriguez, E.E., Sokolov, D.A., Stock, C., Green, M.A., Sobolev, O., Rodriguez-Rivera, J.A., Cao, H., Daoud-Aladine, A.: Magnetic and structural properties near the Lifshitz point in Fe 1+x Te. Phys. Rev. B 88, 165110 (2013)
Martinelli, A.: Symmetry-mode and spontaneous strain analysis of the structural transitions in Fe 1−y Te and REFeAsO compounds. J. Phys.: Condens. Matter 25, 125703 (2013)
Martinelli, A., Palenzona, A., Tropeano, M., Putti, M., Ferdeghini, C., Profeta, G., Emerich, E.: Retention of the tetragonal to orthorhombic structural transition in F-substituted SmFeAsO: a new phase diagram for SmFeAs(O 1−x F x ). Phys. Rev. Lett 106, 227001 (2011)
Martinelli, A., Palenzona, A., Putti, M., Ferdeghini, C.: Microstructural evolution throughout the structural transition in 1111 oxy-pnictides. Phys. Rev. B 85, 224534 (2012)
Martinelli, A., Palenzona, A., Tropeano, M., Ferdeghini, C., Cimberle, M.R., Ritter, C.: Neutron powder diffraction investigation of the structural and magnetic properties of (La 1−y Y y )FeAsO. Phys. Rev. B 80, 214106 (2009)
Kasperkiewicz, K., Bos, J.W.G., Fitch, A.N., Prassides, K., Margadonna, S.: Structural and electronic response upon hole doping of rare-earth iron oxyarsenides Nd 1−x Sr x FeAsO (0 < x ≤0.2). Chem. Commun. 707, 707 (2009)
Margadonna, S., Takabayashi, Y., McDonald, M.T., Kasperkiewicz, K., Mizuguchi, Y., Takano, Y., Fitch, A.N., Suard, E., Prassides, K.: Crystal structure of the new FeSe 1−x superconductor. Chem. Commun. 5607 (2008)
Margadonna, S., Takabayashi, Y., Ohishi, Y., Mizuguchi, Y., Takano, Y., Kagayama, T., Nakagawa, T., Takata, M., Prassides, K.: Pressure evolution of the low-temperature crystal structure and bonding of the superconductor FeSe (T c = 37 K). Phys. Rev. B 80, 064506 (2009)
Boher, P., Garnier, P., Gavarri, J.R., Hewat, A.W.: Monoxyde quadratique PbO α(I): description de la transition structurale ferroelastique. J. Sol. St. Chem. 7, 343 (1985)
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This work has been supported by FP7 European Project SUPERIRON (Grant Agreement No. 283204).
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Martinelli, A. Crystallochemistry of Fe-Based Superconductors: Interplay Between Chemical, Structural and Physical Properties in the Fe(Se,Te) and 1111-Type Systems. J Supercond Nov Magn 28, 1103–1106 (2015). https://doi.org/10.1007/s10948-014-2667-0
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DOI: https://doi.org/10.1007/s10948-014-2667-0